We are continuing longitudinal observations on TRIC agent infections in several populations, including American Indian children, Samoans living in San Francisco, Tunisian children, and local patients in San Francisco. The longitudinal studies on American Indian children are carried out mainly at boarding schools in Nevada, Utah, and Arizona. TRIC antigens in conjunctival scrapings are detected by immunofluorescence, and attempts are made to grow TRIC agents in irradiated cell cultures, where positive inclusions are detected by iodine stains. Antibodies in serum and tears are detected by complement-fixation (group-reactive) and by immunofluorescence with specific TRIC antigens of groups A - E and LGV I - III. We are continuing to evaluate the relative concentration of antibodies in serum and tears of patients infected with TRIC agents, considering as variables age of patient, duration of infection, intensity of infection (as judged by relative prevalence of TRIC agent at the local site), antigenic type of TRIC agent, geographic location and coexistent bacterial infection. Controlled, double blind trials of chemotherapeutic agents are being carried out, to further evaluate tetracycline and other drugs administered in various treatment regimens. Evaluation is based on clinical response as assessed by several ophthalmologists, immunofluorescent assay of TRIC agent on conjunctival scrapings, antibody titers, drug levels, and microbial flora of the eye.